Adjustable Drum Flap for Uniform Grain Size in Cold Recyclers
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Solution Overview
Problem
Existing ground working machines face challenges in achieving reproducible crushing of ground surfaces and traffic surfaces due to inhomogeneous grain size distribution and potential damage from oversized fragments, which affects the quality of the work result and increases operational resistance.
Innovation Solution
A two-part drum flap design with a pivotable upper part and an adjustable lower part in a telescoping or arc shape, allowing for flexible positioning to maintain an optimal distance from the milling drum, preventing oversized fragments from entering the mixing chamber and reducing operational resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the milling drum operates against the direction of travel, then the machine can process materials efficiently, but slabs break out of the surface course and create inhomogeneous grain size distribution
Solution Approach 1:
The drum flap is positioned in advance before the milling drum to pre-crush slabs and prevent them from breaking out during milling. This preliminary crushing action ensures that material is processed more uniformly and prevents the formation of oversized fragments that would create inhomogeneous grain size distribution.
Solution Approach 2:
The drum flap acts as an intermediary element between the ground surface and the milling drum. It intercepts and pre-crushes slabs before they reach the milling drum, thereby mediating the crushing process to achieve more uniform grain size distribution while maintaining efficient material processing.
2Device complexity
If the drum flap position is fixed, then the machine structure is simple, but the grain size distribution cannot be optimized for different working conditions
Solution Approach 1:
The drum flap is made adjustable in its position relative to the milling drum, allowing operators to modify the gap distance according to different working conditions and desired grain size distributions. This dynamic adjustability transforms a static structure into a flexible system that can adapt to various requirements without significantly increasing structural complexity.
Solution Approach 2:
The position parameter of the drum flap (specifically the gap distance to the milling drum) can be changed to optimize grain size distribution for different working conditions. By adjusting this geometric parameter, the system achieves versatility in producing different material characteristics while maintaining a relatively simple overall structure.
3Manufacturing precision
If crusher bars are arranged inside the drum housing, then fragment crushing is improved, but maintenance becomes difficult and material build-up increases operational resistance
Solution Approach 1:
The crushing function is extracted from the interior of the drum housing and relocated to the drum flap positioned in front of the milling drum. This extraction eliminates the need for internal crusher bars, making the system easier to maintain while preventing material build-up that would increase operational resistance. The drum flap provides external crushing without the maintenance problems of internal components.
Data Source
AI summary
In a ground working machine for working ground surfaces or traffic surfaces, in particular cold recycler or soil stabilizer as a self-propelled machine or attachment unit, featuring a machine frame, featuring a milling/mixing drum rotating transversely to the working direction of the machine frame, featuring a drum housing enclosing the milling/mixing drum and resting on the ground surface during the milling operation that forms a mixing chamber for crushing the milled material and/or mixing the milled material with additives, where the milling/mixing drum is height-adjustable for adjustment of a selectable milling depth, featuring a pivotable drum flap arranged, as a minimum, at the front end of the drum housing as seen in working direction, and featuring a controller for, as a minimum, the working process, it is provided for the following features to be achieved: the drum flap is, as a minimum, of two-part design and comprises no less than one upper part and one lower part, in which design no less than one part is pivotable and no less than one further part is adjustable in a telescoping fashion linearly or in the shape of an arc.